Renal Dysfunction

Question 1

Pain medications to
-avoid
-use in CKD

Answer 1

NSAIDs
Strong opioids - adverse effects more pronounced in renal impairment
-can use low-dose fentanyl if codeine not an option, no active metabolites excreted through kidneys

Weak opioids - can consider, but adverse effects can be more pronounced in renal impairment
-codeine

Question 2

Causes of drug-induced nephrotoxicity

Answer 2

Direct nephrotoxicity
Aminoglycosides - ATN
Amphotericin
Cytotoxics
Insecticides/herbicides
Cocaine

Volume depletion
-diuretics

Hypoperfusion
-NSAIDs/COX2inh

Interstitial damage
Lithium

Vasoconstrictors
Immunosuppressants - ischemia
-ciclosporin, tacrolimus
Radioconstrast

Question 3

Nephrotoxic pathological states

Answer 3

Hypoperfusion
Sepsis - endotoxins, inflammatory markers => damage vascular endothelium => thrombosis
Rhabdomyolysis
Hepatorenal syndrome - association between ESLD + renal vasoconstriction

Question 4

When should creatinine clearance be used over eGFR

Answer 4

Older adults
Patients on nephrotoxics
Extremes of muscle mass/weight
Medication with a narrow therapeutic index
Patients on DOACs

Used to adjust the drug dosing

Question 5

Pharmacokinetic considerations to make in CKD

Answer 5

Elimination half life - prolonged in CKD if drug is predominantly excreted by the kidney
-accumulates quickly unless dosing regimen also prolonged

Adjust drug dosing in renal impairment by
-reducing the amount of the regular dose given
-extending the interval between regular doses

Question 6

Pharmacological management of AKI

Answer 6

DHx

Withdraw potential nephrotoxics, consider future use

Dose adjustment in drugs/active metabolites that are renally excreted

Avoid
ACEi, NSADs, radiocontrast, aminoglycosides where possible

Monitor [drug]

Question 7

Rehydration in AKI

Answer 7

1st line - 0.9% saline
Use NaHCO3 1.26% if hypovolemic AKI with metabolic acidosis

Aim for volume repletion
-250-500ml saline fluid boluses
Maintenance fluids
-monitor fluid balance

Question 8

Diuretic use in CKD

Answer 8

Loop - if fluid overloaded/hyperkalemic/HTN
-urgent = furosemide IV

Thiazides ineffective in severe impairment (eGFR U30)
Potassium sparing diuretics - avoid due to hyperkalemia risk

Question 9

ACEi, ARB use in CKD

Answer 9

Can be used but need to
-monitor BP
-titrate dose and monitor renal function

Creatinine can increase by 20% but this is not a absolute reason to discontinue

Do not use in
-bilateral renal artery stenosis
-renal artery stenosis in patient with only 1 functioning kidney
-widespread vascular disease => compromising blood flow

Question 9

SGLT2 inh use in CKD

Answer 9

Dapagliflozin - can slow progression of CKD and lower risk of kidney failure
-add on to optimized standard care

Can use in eGFR 25 AND
-T2DM or
-uACR 22.6mg/mol+

Question 10

BP control in CKD

Answer 10

CKD uACR U70 - 140/90
CKD uACR 70+ - 130/80

uACR U30 - regular HTN management
uACR 30+ - ACEi/ARB

Dietary salt restriction
Multiple HTN meds
Titrate up ACEi/ARB
Reduce dosing frequency where possible

Question 11

Medications that affect K balance

Answer 11

Contain K - laxatives
K in serum - ACEi, ARB, spironolactone, NSAIDs
Prevent intracellular buffering of K - Bb, digoxin